求過程,1樓宇瑩玉崇遠樓上把答案給你了,過程我給吧xyyxy乘積的導數, ... z`y=1/y. dz=1/xdx+1/ydy. z=ln(x+y). z`x=1/(x+y). z`y=1/(x+y).
確定! 回上一頁